Publications

monodelphis domestica: a new animal model for studies in photodermatology.		2013	3628511
close association between paralogous multiple isomirs and paralogous/orthologues mirna sequences implicates dominant sequence selection across various animal species.	micrornas (mirnas) are crucial negative regulators of gene expression at the post-transcriptional level. next-generation sequencing technologies have identified a series of mirna variants (named isomirs). in this study, paralogous isomir assemblies (from the mirna locus) were systematically analyzed based on data acquired from deep sequencing data sets. evolutionary analysis of paralogous (members in mirna gene family in a specific species) and orthologues (across different animal species) mirna ...	2013	23856130
the oocyte of a new world marsupial, monodelphis domestica: structure, formation, and function of the enveloping mucoid layer.	ovulated oocytes of the gray short-tailed opossum monodelphis domestica are surrounded by a thin zona pellucida and are devoid of a cumulus oophorus. in the ampulla of the oviduct, oocytes acquire a thick mucoid layer composed of concentrically arranged fibrillar material. exocytosis by the secretory cells of the oviductal epithelium occurs in the region of the oviduct adjacent to the egg. this suggests that the oocyte-zona-mucus layer complex may influence the oviductal epithelium to secrete. d ...	2013	3612053
dietary effects on hematologic and serum chemical values in gray short-tailed opossums (monodelphis domestica).	at the time of weaning (8 weeks), 57 gray short-tailed opossums (monodelphis domestica) were placed in four dietary groups. one group was fed a horsemeat-based diet that had been used for 2.5 years in our colony, and three groups were fed three different commercial fox food diets. after the animals had reached sexual maturity (6 months), blood samples were collected and subjected to standard hematologic and serum chemical assays. significant differences were observed among the dietary groups and ...	2013	3754293
photic preference of the short-tailed opossum (monodelphis domestica).	the gray short-tailed opossum (monodelphis domestica) is a nocturnal south american marsupial that has been gaining popularity as a laboratory animal. however, compared to traditional laboratory animals like rats, very little is known about its behavior, either in the wild or in a laboratory setting. here we investigated the photic preference of the short-tailed opossum. opossums were placed in a circular testing arena and allowed to move freely between dark (0 lux) and light (∼1.4, 40, or 400 l ...	2014	24709041
domestic, peridomestic and wild hosts in the transmission of trypanosoma cruzi in the caatinga area colonised by triatoma brasiliensis.	the role played by different mammal species in the maintenance of trypanosoma cruzi is not constant and varies in time and place. this study aimed to characterise the importance of domestic, wild and peridomestic hosts in the transmission of t. cruzi in tauá, state of ceará, caatinga area, brazil, with an emphasis on those environments colonised by triatoma brasiliensis. direct parasitological examinations were performed on insects and mammals, serologic tests were performed on household and out ...	2014	25410992
phylogenetic analysis and positive-selection site detecting of vascular endothelial growth factor family in vertebrates.	vascular endothelial growth factor (vegf), known to play an important role in vascular homeostasis, vascular integrity and angiogenesis, is little known about the evolutionary relationship of its five members especially the role of gene duplication and natural selection in the evolution of the vegf family. in this study, seventy-five full-length cdna sequences from 33 vertebrate species were extracted from the ncbi's genbank, uniprot protein database and the ensembl database. by phylogenetic ana ...	2014	24200960
development of the ethmoid in caluromys philander (didelphidae, marsupialia) with a discussion on the homology of the turbinal elements in marsupials.	homology of turbinals, or scroll bones, of the mammalian ethmoid bone is poorly known and complicated by a varied terminology. positionally, there are two main types of ossified adult turbinals known as endoturbinals and ectoturbinals, and their cartilaginous precursors are called ethmoturbinals and frontoturbinals, respectively. endoturbinals are considered to be serially homologous due to similarity in their developmental patterns. consequently, endoturbinals from mammals with differing number ...	2014	25312361
sources of blood meals of sylvatic triatoma guasayana near zurima, bolivia, assayed with qpcr and 12s cloning.	in this study we compared the utility of two molecular biology techniques, cloning of the mitochondrial 12s ribosomal rna gene and hydrolysis probe-based qpcr, to identify blood meal sources of sylvatic chagas disease insect vectors collected with live-bait mouse traps (also known as noireau traps). fourteen t. guasayana were collected from six georeferenced trap locations in the andean highlands of the department of chuquisaca, bolivia.	2014	25474154
ontogenetic allometry in the thoracolumbar spine of mammal species with differing gait use.	vertebrae are serially homologous structures with tight integration through their evolution and development. however, in mammals, the thoracic and lumbar regions are morphologically and functionally differentiated. we test the hypothesis that locomotor specialization is associated with altered post-natal growth patterns in vertebrae from different vertebral regions. we use longitudinal data to examine thoracolumbar growth in two specialized half-bounding (oryctolagus cuniculus and chinchilla lan ...	2014	24617990
fixpred: a resource for correction of erroneous protein sequences.	protein databases are heavily contaminated with erroneous (mispredicted, abnormal and incomplete) sequences and these erroneous data significantly distort the conclusions drawn from genome-scale protein sequence analyses. in our earlier work we described the mispred resource that serves to identify erroneous sequences; here we present the fixpred computational pipeline that automatically corrects sequences identified by mispred as erroneous. the current version of the associated fixpred database ...	2014	24705206
domestic, peridomestic and wild hosts in the transmission of trypanosoma cruzi in the caatinga area colonised by triatoma brasiliensis.	the role played by different mammal species in the maintenance of trypanosoma cruzi is not constant and varies in time and place. this study aimed to characterise the importance of domestic, wild and peridomestic hosts in the transmission of t. cruzi in tauá, state of ceará, caatinga area, brazil, with an emphasis on those environments colonised by triatoma brasiliensis. direct parasitological examinations were performed on insects and mammals, serologic tests were performed on household and out ...	2014	25165976
functional and evolutionary aspects of axial stability in euarchontans and other mammals.	the presence of a stable thoracolumbar region, found in many arboreal mammals, is considered advantageous for bridging and cantilevering between discontinuous branches. however, no study has directly explored the link between osteological features cited as enhancing axial stability and the frequency of cantilevering and bridging behaviors in a terminal branch environment. to fill this gap, we collected metric data on costal and vertebral morphology of primate and nonprimate mammals known to cant ...	2014	24288155
paternal x inactivation does not correlate with x chromosome evolutionary strata in marsupials.	x chromosome inactivation is the transcriptional silencing of one x chromosome in the somatic cells of female mammals. in eutherian mammals (e.g. humans) one of the two x chromosomes is randomly chosen for silencing, with about 15% (usually in younger evolutionary strata of the x chromosome) of genes escaping this silencing. in contrast, in the distantly related marsupial mammals the paternally derived x is silenced, although not as completely as the eutherian x. a chromosome wide examination of ...	2014	25539578
a transcriptome resource for the koala (phascolarctos cinereus): insights into koala retrovirus transcription and sequence diversity.	the koala, phascolarctos cinereus, is a biologically unique and evolutionarily distinct australian arboreal marsupial. the goal of this study was to sequence the transcriptome from several tissues of two geographically separate koalas, and to create the first comprehensive catalog of annotated transcripts for this species, enabling detailed analysis of the unique attributes of this threatened native marsupial, including infection by the koala retrovirus.	2014	25214207
heterochrony in the regulation of the developing marsupial limb.	at birth, marsupial neonates have precociously developed forelimbs. the development of the tammar wallaby (macropus eugenii) hindlimbs lags significantly behind that of the forelimbs. this differs from the grey short-tailed opossum, monodelphis domestica, which has relatively similar fore- and hindlimbs at birth. this study examines the expression of the key patterning genes tbx4, tbx5, pitx1, fgf8, and shh in developing limb buds in the tammar wallaby.	2014	24115631
myosin isoform expression in the prehensile tails of didelphid marsupials: functional differences between arboreal and terrestrial opossums.	prehensile tails are defined as having the ability to grasp objects and are commonly used as a fifth appendage during arboreal locomotion. despite the independent evolution of tail prehensility in numerous mammalian genera, data relating muscle structure, physiology, and function of prehensile tails are largely incomplete. didelphid marsupials make an excellent model to relate myosin heavy chain (mhc) isoform fiber type with structure/function of caudal muscles, as all opossums have a prehensile ...	2014	24832677
evolution of mammalian sensorimotor cortex: thalamic projections to parietal cortical areas in monodelphis domestica.	the current experiments build upon previous studies designed to reveal the network of parietal cortical areas present in the common mammalian ancestor. understanding this ancestral network is essential for highlighting the basic somatosensory circuitry present in all mammals, and how this basic plan was modified to generate species specific behaviors. our animal model, the short-tailed opossum (monodelphis domestica), is a south american marsupial that has been proposed to have a similar ecologi ...	2014	25620915
distribution and function of trkb receptors in the developing brain of the opossum monodelphis domestica.	the expression, development pattern, spatiotemporal distribution, and function of trkb receptors were investigated during the postnatal brain development of the opossum. full-length trkb receptor expression was detectable in the newborn opossum, whereas three different short forms that are expressed in the adult brain were almost undetectable in the newborn opossum brain. the highest level of full-length trkb receptor expression was observed at p35, which corresponds to the time of eye opening. ...	2014	24443161
the cellular composition of the marsupial neocortex.	in the current investigation we examined the number and proportion of neuronal and non-neuronal cells in the primary sensory areas of the neocortex of a south american marsupial, the short-tailed opossum (monodelphis domestica). the primary somatosensory (s1), auditory (a1), and visual (v1) areas were dissected from the cortical sheet and compared with each other and the remaining neocortex using the isotropic fractionator technique. we found that although the overall sizes of v1, s1, a1, and th ...	2014	24414857
chromosome-wide profiling of x-chromosome inactivation and epigenetic states in fetal brain and placenta of the opossum, monodelphis domestica.	evidence from a few genes in diverse species suggests that x-chromosome inactivation (xci) in marsupials is characterized by exclusive, but leaky inactivation of the paternally derived x chromosome. to study the phenomenon of marsupial xci more comprehensively, we profiled parent-of-origin allele-specific expression, dna methylation, and histone modifications in fetal brain and extra-embryonic membranes in the gray, short-tailed opossum (monodelphis domestica). the majority of x-linked genes (15 ...	2014	24065774
torpor at high ambient temperature in a neotropical didelphid, the grey short-tailed opossum (monodelphis domestica).	the grey short-tailed opossum, monodelphis domestica, has been an established research animal for more than five decades, but relatively, little is known about its thermophysiology. here we studied core body temperature (t b) and metabolic rate (mr) of female adult m. domestica housed in the laboratory at an ambient temperature (t a) of 26 °c. in expanding previous reports, the average recorded core t b of m. domestica was 34.3 °c. the t b of an individual m. domestica can drop below 30 °c (mini ...	2014	25142634
function of pretribosphenic and tribosphenic mammalian molars inferred from 3d animation.	appearance of the tribosphenic molar in the late jurassic (160 ma) is a crucial innovation for food processing in mammalian evolution. this molar type is characterized by a protocone, a talonid basin and a two-phased chewing cycle, all of which are apomorphic. in this functional study on the teeth of late jurassic dryolestes leiriensis and the living marsupial monodelphis domestica, we demonstrate that pretribosphenic and tribosphenic molars show fundamental differences of food reduction strateg ...	2014	25091547
modeling sunscreen-mediated melanoma prevention in the laboratory opossum (monodelphis domestica).		2014	24931873
body size and the small branch niche: using marsupial ontogeny to model primate locomotor evolution.	recently proposed ancestral locomotor and morphological 'stages' leading to the evolution of primates have emphasized small body size, and a transition from a clawed non-grasping stage, to a clawed, grasping stage with clawless opposable hallux, to a fully-nailed primate with grasping extremities. this evolutionary transition was presumably associated with frequent use of the small branch niche. to model elements of these evolutionary transitions, we investigate how body size, substrate size, su ...	2014	24508352
cellular basis of differential limb growth in postnatal gray short-tailed opossums (monodelphis domestica).	while growth has been studied extensively in invertebrates, the mechanisms by which it is controlled in vertebrates, particularly in mammals, remain poorly understood. in this study, we investigate the cellular basis of differential limb growth in postnatal monodelphis domestica, the gray short-tailed opossum, to gain insights into the mechanisms regulating mammalian growth. opossums are an ideal model for the study of growth because they are born with relatively large, well-developed forelimbs ...	2014	24500902
genome-wide histone state profiling of fibroblasts from the opossum, monodelphis domestica, identifies the first marsupial-specific imprinted gene.	imprinted genes have been extensively documented in eutherian mammals and found to exhibit significant interspecific variation in the suites of genes that are imprinted and in their regulation between tissues and developmental stages. much less is known about imprinted loci in metatherian (marsupial) mammals, wherein studies have been limited to a small number of genes previously known to be imprinted in eutherians. we describe the first ab initio search for imprinted marsupial genes, in fibrobl ...	2014	24484454
age-dependent transcriptome and proteome following transection of neonatal spinal cord of monodelphis domestica (south american grey short-tailed opossum).	this study describes a combined transcriptome and proteome analysis of monodelphis domestica response to spinal cord injury at two different postnatal ages. previously we showed that complete transection at postnatal day 7 (p7) is followed by profuse axon growth across the lesion with near-normal locomotion and swimming when adult. in contrast, at p28 there is no axon growth across the lesion, the animals exhibit weight-bearing locomotion, but cannot use hind limbs when swimming. here we examine ...	2014	24914927
immunohistological study of the endometrial stromal fibroblasts in the opossum, monodelphis domestica: evidence for homology with eutherian stromal fibroblasts.	molecular phylogenetic studies suggest that the hemochorial placentation and decidualization are ancestral traits of eutherian mammals. while the origin of the placental tissue is well understood, the origin of the decidual cells is unclear. here we address the origin of decidual cells by examining the expression patterns of six transcription factors (tfs) as well as four structural proteins in the endometrium of a marsupial, monodelphis domestica, and compared them with the patterns known from ...	2014	24740599
arrested development of the dorsal column following neonatal spinal cord injury in the opossum, monodelphis domestica.	developmental studies of spinal cord injury in which regrowth of axons occurs across the site of transection rarely distinguish between the recovery of motor-controlling pathways and that of ascending axons carrying sensory information. we describe the morphological changes that occur in the dorsal column (dc) of the grey short-tailed opossum, monodelphis domestica, following spinal cord injury at two early developmental ages. the spinal cords of opossums that had had their mid-thoracic spinal c ...	2015	25487408
exogenous retinoic acid induces digit reduction in opossums (monodelphis domestica) by disrupting cell death and proliferation, and apical ectodermal ridge and zone of polarizing activity function.	retinoic acid (ra) is a vitamin a derivative. exposure to exogenous ra generates congenital limb malformations (clms) in species from frogs to humans. these clms include but are not limited to oligodactyly and long-bone hypoplasia. the processes by which exogenous ra induces clms in mammals have been best studied in mouse, but as of yet remain unresolved.	2015	25656823
rate of evolutionary change in cranial morphology of the marsupial genus monodelphis is constrained by the availability of additive genetic variation.	we tested the hypothesis that the rate of marsupial cranial evolution is dependent on the distribution of genetic variation in multivariate space. to do so, we carried out a genetic analysis of cranial morphological variation in laboratory strains of monodelphis domestica and used estimates of genetic covariation to analyse the morphological diversification of the monodelphis brevicaudata species group. we found that within-species genetic variation is concentrated in only a few axes of the morp ...	2015	25818173
marsupials and monotremes possess a novel family of mhc class i genes that is lost from the eutherian lineage.	major histocompatibility complex (mhc) class i genes are found in the genomes of all jawed vertebrates. the evolution of this gene family is closely tied to the evolution of the vertebrate genome. family members are frequently found in four paralogous regions, which were formed in two rounds of genome duplication in the early vertebrates, but in some species class is have been subject to additional duplication or translocation, creating additional clusters. the gene family is traditionally group ...	2015	26194104
amelotin gene structure and expression during enamel formation in the opossum monodelphis domestica.	amelotin (amtn) is an ameloblast-secreted protein that belongs to the secretory calcium-binding phosphoprotein family, which also includes the enamel matrix proteins amelogenin, ameloblastin and enamelin. although amtn is supposed to play an important role in enamel formation, data were long limited to the rodents, in which it is expressed during the maturation stage. recent comparative studies in sauropsids and amphibians revealed that (i) amtn was expressed earlier, i.e. as soon as ameloblasts ...	2015	26186457
ultrastructural analysis between fetal and adult wound healing process of marsupial opossum skin.	the opossum delivers a newborn baby equivalent to tremature fetus state by postpregnancy. the peculiarity is advantageous for studies of fetus, because operations to take out fetus from the uterus of a mother are not necessary. when mammalian skin is wounded by full-thickness excision, fetal and adult wound healing processes differ. fetal-type wound healing does not leave a scar. however, studies of how the fetal wound healing process differs in detail from the adult type are not advanced. we fi ...	2015	25912322
the opossum mhc genomic region revisited.	the gray short-tailed opossum monodelphis domestica is one of the few marsupial species for which a high quality whole genome sequence is available and the major histocompatibility complex (mhc) region has been annotated. previous analyses revealed only a single locus within the opossum mhc region, designated modo-ua1, with the features expected for encoding a functionally classical class i α-chain. nine other class i genes found within the mhc are highly divergent and have features usually asso ...	2015	25737310
a comparative examination of odontogenic gene expression in both toothed and toothless amniotes.	a well-known tenet of murine tooth development is that bmp4 and fgf8 antagonistically initiate odontogenesis, but whether this tenet is conserved across amniotes is largely unexplored. moreover, changes in bmp4-signaling have previously been implicated in evolutionary tooth loss in aves. here we demonstrate that bmp4, msx1, and msx2 expression is limited proximally in the red-eared slider turtle (trachemys scripta) mandible at stages equivalent to those at which odontogenesis is initiated in mic ...	2015	25678399
the transcriptomic evolution of mammalian pregnancy: gene expression innovations in endometrial stromal fibroblasts.	the endometrial stromal fibroblast (esf) is a cell type present in the uterine lining of therian mammals. in the stem lineage of eutherian mammals, esf acquired the ability to differentiate into decidual cells in order to allow embryo implantation. we call the latter cell type "neo-esf" in contrast to "paleo-esf" which is homologous to eutherian esf but is not able to decidualize. in this study, we compare the transcriptomes of esf from six therian species: opossum (monodelphis domestica; paleo- ...	2016	27401177
novel babesia and hepatozoon agents infecting non-volant small mammals in the brazilian pantanal, with the first record of the tick ornithodoros guaporensis in brazil.	taking into account the diversity of small terrestrial mammals of the pantanal, the present study aimed to verify the occurrence of infection by ehrlichia spp., anaplasma spp., rickettsia spp., hepatozoon spp., babesia spp. and parasitism by ticks in non-volant small mammals collected in the brazilian pantanal. samples of blood, liver and spleen were collected from 64 captured animals, 22 marsupials and 42 rodents. pathogen detection was performed by the use of genus-specific polymerase chain re ...	2016	26782931
transcriptomic changes associated with pregnancy in a marsupial, the gray short-tailed opossum monodelphis domestica.	live birth has emerged as a reproductive strategy many times across vertebrate evolution; however, mammals account for the majority of viviparous vertebrates. marsupials are a mammalian lineage that last shared a common ancestor with eutherians (placental mammals) over 148 million years ago. marsupials are noted for giving birth to highly altricial young after a short gestation, and represent humans' most distant viviparous mammalian relatives. here we ask what insight can be gained into the evo ...	2016	27598793
facial mechanosensory influence on forelimb movement in newborn opossums, monodelphis domestica.	the opossum, monodelphis domestica, is born very immature but crawls, unaided, with its forelimbs (fl) from the mother's birth canal to a nipple where it attaches to pursue its development. what sensory cues guide the newborn to the nipple and trigger its attachment to it? previous experiments showed that low intensity electrical stimulation of the trigeminal ganglion induces fl movement in in vitro preparations and that trigeminal innervation of the facial skin is well developed in the newborn. ...	2016	26848758
the evolution of whisker-mediated somatosensation in mammals: sensory processing in barrelless s1 cortex of a marsupial, monodelphis domestica.	movable tactile sensors in the form of whiskers are present in most mammals, but sensory coding in the cortical whisker representation has been studied almost exclusively in mice and rats. many species that possess whiskers lack the modular "barrel" organization found in the primary somatosensory cortex (s1) of mice and rats, but it is unclear how whisker-related input is represented in these species. we used single-unit extracellular recording techniques to characterize receptive fields and res ...	2016	27098555
the ut family of mhc class i loci unique to non-eutherian mammals has limited polymorphism and tissue specific patterns of expression in the opossum.	the major histocompatibility complex (mhc) class i family of genes encode for molecules that have well-conserved structures, but have evolved to perform diverse functions. the availability of the gray, short-tailed opossum, monodelphis domestica whole genome sequence has allowed for analysis of mhc class i gene content in this marsupial. utilization of a novel method to search for mhc related domain structures revealed a previously unknown family of mhc class i-related genes. these genes, named ...	2016	27825298
conserved and divergent expression patterns of markers of axial development in the laboratory opossum, monodelphis domestica.	previous comparative studies suggest that the requirement for nodal in epiblast and hypoblast development is unique to mammalians. expression of anterior visceral endoderm (ave) genes in the visceral endoderm and of their orthologs in the hypoblast may be unique to mammalians and avians, and is absent in the reptilian hypoblast. axis formation in reptiles is signaled by the formation of the posterior marginal epiblast (pme), which expresses a series of primitive streak genes. to assess the phylo ...	2016	27666927
functional conservation of the lncrna neat1 in the ancestrally diverged marsupial lineage: evidence for neat1 expression and associated paraspeckle assembly during late gestation in the opossum monodelphis domestica.	long non-coding rnas (lncrnas) are widely expressed and play various roles in cell homeostasis. however, because of their low conservation at the sequence level, recapitulating lncrna evolutionary history is often challenging. while performing an ultrastructural analysis of viral particles present in uterine glands of gestating opossum females, we serendipitously noticed the presence of numerous structures similar to paraspeckles, nuclear bodies which in human and mouse cells are assembled aroun ...	2016	27315396
cellular and molecular drivers of differential organ growth: insights from the limbs of monodelphis domestica.	a fundamental question in biology is "how is growth differentially regulated during development to produce organs of particular sizes?" we used a new model system for the study of differential organ growth, the limbs of the opossum (monodelphis domestica), to investigate the cellular and molecular basis of differential organ growth in mammals. opossum forelimbs grow much faster than hindlimbs, making opossum limbs an exceptional system with which to study differential growth. we first used the g ...	2016	27194412
asp-ase activity of the opossum granzyme b supports the role of granzyme b as part of anti-viral immunity already during early mammalian evolution.	granzyme b is one of the key effector molecules in our defense against viruses and intracellular bacteria. this serine protease together with the pore forming protein perforin, induces caspase or bid-dependent apoptosis in target cells. here we present the first characterization of a granzyme b homolog, the grathepsodenase, in a non-placental mammal, the american opossum (monodelphis domestica). the recombinant enzyme was produced in a human cell line and used to study its primary and extended c ...	2016	27152961
identification of the mrna encoding interleukin-6 and its receptor, interleukin-6 receptor α, in five marsupial species.	expressed coding sequences for interleukin-6 (il-6) and interleukin-6 receptor α (il-6r) were examined in five marsupial species. full length expressed coding sequences for il-6 and il-6r were identified and characterized in the gray short-tailed opossum (monodelphis domestica). for il-6, ∼225 bp fragments of the mrna sequence were identified in the red-tailed phascogale (phascogale calura), kultarr (antechinomys laniger), and stripe-faced dunnart (sminthopsis macroura), while ∼563 bp fragments ...	2016	27431929
comparative gene expression analyses reveal heterochrony for sox9 expression in the cranial neural crest during marsupial development.	compared to placental mammals, marsupials have short gestation period, and their neonates are relatively immature. despite these features, marsupial neonates must travel from the birth canal to the teat, suckle and digest milk to complete development. thus, certain organs and tissues of marsupial neonates, such as forelimbs to crawl and jaw elements to suckle, must develop early. previous reports showed that cranial neural crest (cnc) cells, as the source of ectomesenchyme of jaw elements, are g ...	2016	24934187
angioarchitecture and morphology of temporomandibular joint of monodelphis domestica.	the opossum monodelphis domestica presents movement of the temporomandibular joint (tmj) reflecting adaptation to eating habits similar to movement in humans, but the structure of the tmj is not yet known. thus, nine young m. domestica, of both sexes were weighed, anesthetized with xylazine (10 mg kg(-1) ), and ketamine (70 mg kg(-1) ) and processed for: 1. the analyses of the macroscopic angioarchitecture after latex injection, as well as the topography of the tmj; 2. the analysis of microvascu ...	2016	27324400
evolution of the genotype-to-phenotype map and the cost of pleiotropy in mammals.	evolutionary studies have long emphasized that the genetic architecture of traits holds important microevolutionary consequences. yet, studies comparing the genetic architecture of traits across species are rare, and discussions of the evolution of genetic systems are made on theoretical arguments rather than on empirical evidence. here, we compared the genetic architecture of cranial traits in two different mammalian model organisms: the gray short-tailed opossum, monodelphis domestica, and the ...	2016	27784721
differential morphology of the superior olivary complex of meriones unguiculatus and monodelphis domestica revealed by calcium-binding proteins.	in mammals, the superior olivary complex (soc) of the brainstem is composed of nuclei that integrate afferent auditory originating from both ears. here, the expression of different calcium-binding proteins in subnuclei of the soc was studied in distantly related mammals, the mongolian gerbil (meriones unguiculatus) and the gray short-tailed opossum (monodelphis domestica) to get a better understanding of the basal nuclear organization of the soc. combined immunofluorescence labeling of the calci ...	2016	26792006
comparative anatomy of neonates of the three major mammalian groups (monotremes, marsupials, placentals) and implications for the ancestral mammalian neonate morphotype.	the existing different modes of reproduction in monotremes, marsupials and placentals are the main source for our current understanding of the origin and evolution of the mammalian reproduction. the reproductive strategies and, in particular, the maturity states of the neonates differ remarkably between the three groups. monotremes, for example, are the only extant mammals that lay eggs and incubate them for the last third of their embryonic development. in contrast, marsupials and placentals ar ...	2017	28960296
uterine remodelling during pregnancy and pseudopregnancy in the brushtail possum (trichosurus vulpecula; phalangeridae).	the formation of a placenta is critical for successful mammalian pregnancy and requires remodelling of the uterine epithelium. in eutherian mammals, remodelling involves specific morphological changes that often correlate with the mode of embryonic attachment. given the differences between marsupial and eutherian placentae, formation of a marsupial placenta may involve patterns of uterine remodelling that are different from those in eutherians. here we present a detailed morphological study of t ...	2017	28397980
composition of marsupial zona pellucida: a molecular and phylogenetic approach.	the zona pellucida (zp) is an extracellular matrix that surrounds mammalian oocytes. in eutherians it is formed from three or four proteins (zp1, zp2, zp3, zp4). in the few marsupials that have been studied, however, only three of these have been characterised (zp2, zp3, zp4). nevertheless, the composition in marsupials may be more complex, since a duplication of the zp3 gene was recently described in one species. the aim of this work was to elucidate the zp composition in marsupials and relate ...	2017	29162213
the transcriptome of thedidelphis virginianaopossum kidney ok proximal tubule cell line.	the ok cell line derived from the kidney of a female opossumdidelphis virginianahas proven to be a useful model in which to investigate the unique regulation of ion transport and membrane trafficking mechanisms in the proximal tubule (pt). sequence data and comparison of the transcriptome of this cell line to eutherian mammal pts would further broaden the utility of this culture model. however, the genomic sequence ford. virginianais not available and although a draft genome sequence for the opo ...	2017	28615248
a pronounced uterine pro-inflammatory response at parturition is an ancient feature in mammals.	regulating maternal immunity is necessary for successful human pregnancy. whether this is needed in mammals with less invasive placentation is subject to debate. indeed, the short gestation times in marsupials have been hypothesized to be due to a lack of immune regulation during pregnancy. alternatively, the maternal marsupial immune system may be unstimulated in the absence of a highly invasive placenta. transcripts encoding pro-inflammatory cytokines were found to be overrepresented in the wh ...	2017	29070722
comparison of 6 injectable anesthetic regimens and isoflurane in gray short-tailed opossums (monodelphis domestica).	gray short-tailed opossums are used in a wide variety of research in the areas of developmental biology, oncology, immunology, and comparative biology. despite many frequent experimental manipulations of these animals under anesthesia, few studies to date have characterized the effects of anesthesia in this species. our aim was to identify safe and effective injectable anesthetic combinations using ketamine and xylazine or ketamine and dexmedetomidine at doses of 40 mg/kg to 100 mg/kg for ketami ...	2017	28903826
embryo implantation evolved from an ancestral inflammatory attachment reaction.	the molecular changes that support implantation in eutherian mammals are necessary to establish pregnancy. in marsupials, pregnancy is relatively short, and although a placenta does form, it is present for only a few days before parturition. however, morphological changes in the uterus of marsupials at term mimic those that occur during implantation in humans and mice. we investigated the molecular similarity between term pregnancy in the marsupials and implantation in eutherian mammals using th ...	2017	28747528
ontogeny of myosin isoform expression and prehensile function in the tail of the gray short-tailed opossum (monodelphis domestica).	terrestrial opossums use their semiprehensile tail for grasping nesting materials as opposed to arboreal maneuvering. we relate the development of this adaptive behavior with ontogenetic changes in myosin heavy chain (mhc) isoform expression from 21 days to adulthood.monodelphis domesticais expected to demonstrate a progressive ability to flex the distal tail up to age 7 mo, when it should exhibit routine nest construction. we hypothesize that juvenile stages (3-7 mo) will be characterized by re ...	2017	28522766
the unique paired retinal vessels of the gray short-tailed opossum (monodelphis domestica) and their relationship to astrocytes and microglial cells.	in marsupials that possess a retinal vasculature, the arterial and venous segments, down to the smallest calibre capillaries, have been shown to occur in pairs. this pattern is seen in the marsupial central nervous system (cns) but not in other tissues in this group or in any tissues in eutherian mammals. the present study aimed to determine if the gray short-tailed opossum (monodelphis domestica), a south american marsupial, possesses double retinal vessels. secondly, we investigated the relati ...	2017	28371527
a new developmental mechanism for the separation of the mammalian middle ear ossicles from the jaw.	multiple mammalian lineages independently evolved a definitive mammalian middle ear (dmme) through breakdown of meckel's cartilage (mc). however, the cellular and molecular drivers of this evolutionary transition remain unknown for most mammal groups. here, we identify such drivers in the living marsupial opossummonodelphis domestica, whose mc transformation during development anatomically mirrors the evolutionary transformation observed in fossils. specifically, we link increases in cellular ap ...	2017	28179517
a new mammalian model system for thalidomide teratogenesis: monodelphis domestica.	from 1957 to 1962, thalidomide caused birth defects in >10,000 children. while the drug was pulled from the market, thalidomide is currently prescribed to treat conditions including leprosy. as a result, a new generation of babies with thalidomide defects is being born in the developing world. this represents a serious problem, as the mechanisms by which thalidomide disrupts development remain unresolved. this lack of resolution is due, in part, to the absence of an appropriate mammalian model f ...	2017	28130151
on the prenatal initiation of t cell development in the opossum monodelphis domestica.	thymus-dependent lymphocytes (t cells) are a critical cell lineage in the adaptive immune system of all jawed vertebrates. in eutherian mammals the initiation of t cell development takes place prenatally and the offspring of many species are born relatively immuno-competent. marsupials, in contrast, are born in a comparatively altricial state and with a less well developed immune system. as such, marsupials are valuable models for studying the peri- and postnatal initiation of immune system deve ...	2017	28052333
cortical plasticity following stripe rearing in the marsupial monodelphis domestica: neural response properties of v1.	the functional organization of the primary visual area (v1) and the importance of sensory experience in its normal development have been well documented in eutherian mammals. however, very few studies have investigated the response properties of v1 neurons in another large class of mammals, or whether sensory experience plays a role in shaping their response properties. thus we reared opossums (monodelphis domestica) in normal and vertically striped cages until they reached adulthood. they were ...	2017	27852732
complete mitochondrial genome of tlacuatzin canescens (grayish mouse opossum).	in this study, we report the complete mitochondrial genome of the grayish mouse opossumm, tlacuatzin canescens. the mitochondrial genome is 16 460 bp in length and has a base composition of a (35.7%), t (31.3%), c (21.3%), and g (11.7%), demonstrating an obvious bias of high at content (67%). the mitochondrial genome contains a typically conserved structure, encoding 13 protein-coding genes (pcgs), 20 transfer rna genes (trna), 2 ribosomal rna genes (12s rrna and 16s rrna), and a control region ...	2017	26714099
a three-dimensional stereotaxic atlas of the gray short-tailed opossum (monodelphis domestica) brain.	the gray short-tailed opossum (monodelphis domestica) is a small marsupial gaining recognition as a laboratory animal in biomedical research. despite numerous studies on opossum neuroanatomy, a consistent and comprehensive neuroanatomical reference for this species is still missing. here we present the first three-dimensional, multimodal atlas of the monodelphis opossum brain. it is based on four complementary imaging modalities: high resolution ex vivo magnetic resonance images, micro-computed ...	2017	29214509
toxoplasma gondii in domestic and wild animals from forest fragments of the municipality of natal, northeastern brazil.	toxoplasmosis stands out as a global disease that has felines as definitive hosts. in the municipality of natal, rio grande do norte state, brazil, two parks are notable for their ecological and social importance. this study aimed to investigate the presence of toxoplasma gondii in short hair cats, bats and small non-volant mammals in these two ecological reserves. altogether, biological samples were obtained from 154 mammals, 92 wild animals from both areas and 62 domestic cats of the parque da ...	2017	25517529
molecular detection of hepatozoon spp. in domestic dogs and wild mammals in southern pantanal, brazil with implications in the transmission route.	hepatozoon parasites comprise intracellular apicomplexan parasites transmitted to vertebrate animals by ingestion of arthropods definitive hosts. the present work aimed to investigate the occurrence of hepatozoon spp. in wild animals, domestic dogs and their respective ectoparasites, in southern pantanal region, central-western brazil, by molecular techniques. between august 2013 and march 2015, 31 coatis (nasua nasua), 78 crab-eating foxes (cerdocyon thous), seven ocelots (leopardus pardalis), ...	2017	28291601
new trypanosoma species, trypanosoma gennarii sp. nov., from south american marsupial in brazilian cerrado.	hundreds of trypanosome species have been described in all mammalian orders, on every continent, including with mixed infections. trypanosomes circulate in the form of sylvatic enzootic infections transmitted by blood-sucking insects that are associated with the host mammals. small wild mammals were caught in a fragment of cerrado terrain on an island in the hydroelectric reservoir of três marias, in the central region of the state of minas gerais, using pitfall and sherman traps with different ...	2017	28847674
on the development of the chondrocranium and the histological anatomy of the head in perinatal stages of marsupial mammals.	an overview of the literature on the chondrocranium of marsupial mammals reveals a relative conservatism in shape and structures. we document the histological cranial anatomy of individuals representing monodelphis domestica, dromiciops gliroides, perameles sp. and macropus eugenii. the marsupial chondrocranium is generally characterized by the great breadth of the lamina basalis, absence of pila metoptica and large otic capsules. its most anterior portion (cupula nasi anterior) is robust, and a ...	2017	28203388
an x chromosome microrna cluster in the marsupial species monodelphis domestica.	micrornas (mirnas) are an important class of posttranscriptional gene expression regulators. in the course of mapping novel marsupial-specific mirnas in the genome of the gray short-tailed opossum, monodelphis domestica, we encountered a cluster of 39 actual and potential mirnas spanning 102 kb of the x chromosome. analysis of the cluster revealed that 37 of the 39 mirnas are predicted to form thermodynamically stable hairpins, and at least 3 members have been directly cloned from m. domestica t ...	2017	21685406
rodents and other small mammal reservoirs in plague foci in northeastern brazil.	plague is an acute, infectious zoonotic disease, primarily of wild rodents and their fleas, that affects humans and other mammals. in brazil, several plague foci are located in the northeast region. plague surveillance based on monitoring of rodents was discontinued in 2007, and the current information on rodent populations is unsatisfactory. our purpose was to update the information on rodents and other small mammals in plague foci in northeastern brazil.	2017	30943181
gene expression profiling of postnatal lung development in the marsupial gray short-tailed opossum (monodelphis domestica) highlights conserved developmental pathways and specific characteristics during lung organogenesis.	after a short gestation, marsupials give birth to immature neonates with lungs that are not fully developed and in early life the neonate partially relies on gas exchange through the skin. therefore, significant lung development occurs after birth in marsupials in contrast to eutherian mammals such as humans and mice where lung development occurs predominantly in the embryo. to explore the mechanisms of marsupial lung development in comparison to eutherians, morphological and gene expression ana ...	2018	30290757
neural coding of whisker-mediated touch in primary somatosensory cortex is altered following early blindness.	sensory systems do not develop and function independently of one another, yet they are typically studied in isolation. effects of multisensory interactions on the developing neocortex can be revealed by altering the ratios of incoming sensory inputs associated with different modalities. we investigated neural responses in primary somatosensory cortex (s1) of short-tailed opossums (monodelphis domestica; either sex) after the elimination of visual input through bilateral enucleation very early in ...	2018	29807911
detection of rickettsia spp. in ticks associated to wild mammals in northeastern brazil, with notes on an undetermined ornithodoros sp. collected from marsupials.	we report tick infestations and rickettsial detection in ticks infesting free-living wild mammals (monodelphis domestica, tolypeutes tricinctus, thrichomys inermis and kerodon rupestris) captured in the caatinga ecoregion of bahia state, northeastern brazil, during september to december 2016. overall, 117 ticks (61 larvae, 25 nymphs, 25 males, 6 females) belonging to two genera, and at least three species were collected: amblyomma auricularium, amblyomma parvum, amblyomma sp., ornithodoros rietc ...	2018	30443697
the mammalian decidual cell evolved from a cellular stress response.	among animal species, cell types vary greatly in terms of number and kind. the number of cell types found within an organism differs considerably between species, and cell type diversity is a significant contributor to differences in organismal structure and function. these observations suggest that cell type origination is a significant source of evolutionary novelty. the molecular mechanisms that result in the evolution of novel cell types, however, are poorly understood. here, we show that a ...	2018	30142145
identification of a novel antisense noncoding rna, alid, transcribed from the putative imprinting control region of marsupial igf2r.	genomic imprinting leads to maternal expression of igf2r in both mouse and opossum. in mouse, the antisense long noncoding (lnc) rna airn, which is paternally expressed from the differentially methylated region (dmr) in the second intron of igf2r, is required to silence the paternal igf2r. in opossum, however, intriguingly, the dmr was reported to be in a different downstream intron (intron 11) and there was no antisense lncrna detected in previous analyses. therefore, clarifying the imprinting ...	2018	30268152
detection of anti-toxoplasma gondii antibodies in small wild mammals from preserved and non-preserved areas in the caatinga biome, a semi-arid region of northeast brazil.	this study was conducted to determine the seroprevalence of anti-toxoplasma gondii antibodies in 152 free-living small wild mammals from distinct regions in the caatinga biome, a semi-arid region in the northeast of brazil: the national park of serra das confusões (npsc), which is a preserved area in the state of piauí, and the municipalities of petrolina and lagoa grande, two non-preserved areas in the state of pernambuco. using the modified agglutination test (mat), we found that 5.3% (4/75) a ...	2018	31014742
ticks, rickettsial and erlichial infection in small mammals from atlantic forest remnants in northeastern brazil.	we evaluated infection by rickettsia spp. and ehrlichia spp in small mammals and their ticks from two atlantic forest conservation areas in the state of rio grande do norte, northeastern brazil. a total of 39 small mammals were captured during 2012-2013, encompassing 33 marsupials (29 didelphis albiventris, four monodelphis domestica), three cricetidae rodents (two necromys lasiurus, one rattus rattus), one caviomorpha rodent (thrichomys apereoides) and two armadillos (euphractus sexcinctus). th ...	2018	30370217
parotid salivary gland basal cell adenocarcinoma in a big-eared opossum (didelphis aurita).	the opossum (family didelphidae) is a marsupial endemic to the americas. apart from the south american short-tailed opossum (monodelphis domestica) and the virginia opossum (didelphis virginiana), there is considerable lack of knowledge about the health and diseases of most opossum species. among these, the big-eared opossum (didelphis aurita) is found in argentina, brazil and paraguay. natural and experimental studies have shown this species to be susceptible to infectious agents with zoonotic ...	2018	29599001
the rod signaling pathway in marsupial retinae.	the retinal rod pathway, featuring dedicated rod bipolar cells (rbcs) and aii amacrine cells, has been intensely studied in placental mammals. here, we analyzed the rod pathway in a nocturnal marsupial, the south american opossum monodelphis domestica to elucidate whether marsupials have a similar rod pathway. the retina was dominated by rods with densities of 338,000-413,000/mm². immunohistochemistry for the rbc-specific marker protein kinase cα (pkcα) and the aii cell marker calretinin reveale ...	2018	30157204
mining and functional verification of calcitonin genes from the genome database.	with more countries in the world entering elderly society, osteoporosis is a common disease among the elderly, especially middle-aged and elderly women. although calcitonin is an effective drug used to treat osteoporosis in clinical practice, it also exists such problems as high cost, short half-life, and high immunogenicity. therefore, to explore more efficient calcitonin has important clinical significance.	2018	29745315
skin structure in newborn marsupials with focus on cutaneous gas exchange.	a morphological and morphometric study of the skin of a variety of newborn marsupials (dasyurus viverrinus, monodelphis domestica, trichosurus vulpecula, isoodon obesulus, perameles nasuta, phascolarctos cinereus, potorous tridactylus, petrogale penicillata, thylogale thetidi, macropus dorsalis) and of a monotreme hatchling (ornithorhynchus anatinus) was undertaken to assess the possibility of cutaneous gas exchange. additionally, the lungs of some of these species were investigated to assess it ...	2018	29947022
cloning and structural analysis of igm (mu chain) and the heavy chain v region repertoire in the marsupial monodelphis domestica.	to address the question of the ig isotype repertoire of non placental mammals, we have examined the ig expression in the marsupial monodelphis domestica (grey short tailed opossum). screening of an opossum spleen cdna library has previously led to the isolation of full length clones for opossum igg (gamma chain), ige (epsilon chain) and iga (alpha chain). we now present the isolation of several cdna clones encoding the entire constant regions of the opossum igm (mu chain). a comparative analysis ...	2018	10579388
landscape of dna methylation on the marsupial x.	dna methylation plays a key role in maintaining transcriptional silence on the inactive x chromosome of eutherian mammals. beyond eutherians, there are limited genome wide data on dna methylation from other vertebrates. previous studies of x borne genes in various marsupial models revealed no differential dna methylation of promoters between the sexes, leading to the conclusion that cpg methylation plays no role in marsupial x-inactivation. using reduced representation bisulfite sequencing, we g ...	2018	29161408
endometrial recognition of pregnancy occurs in the grey short-tailed opossum ( monodelphis domestica).	in human pregnancy, recognition of an embryo within the uterus is essential to support the fetus through gestation. in most marsupials, such as the opossums, pregnancy is shorter than the oestrous cycle and the steroid hormone profile during pregnancy and oestrous cycle are indistinguishable. for these reasons, it was assumed that recognition of pregnancy, as a trait, evolved in the eutherian (placental) stem lineage and independently in wallabies and kangaroos. to investigate whether uterine re ...	2019	31213185
γδ t cells are the predominant t cell type in opossum mammaries during lactation.	milk provides mammalian neonates with nutritional support and passive immunity. this is particularly true in marsupials where young are born highly altricial and lacking many components of a fully functional adaptive immune system. here we investigated the t cell populations in the mammaries of a lactating marsupial, the gray short-tailed opossum monodelphis domestica. immunohistochemistry confirmed the presence of t cells within the opossum mammaries throughout lactation. results of quantifying ...	2019	30768943
rolling of the jaw is essential for mammalian chewing and tribosphenic molar function.	over the past two centuries, mammalian chewing and related anatomical features have been among the most discussed of all vertebrate evolutionary innovations1-3. chief among these features are two characters: the dentary-only mandible, and the tribosphenic molar with its triangulated upper cusps and lower talonid basin3-5. the flexible mandibular joint and the unfused symphysis of ancestral mammals-in combination with transformations of the adductor musculature and palate-are thought to have perm ...	2019	30760927
aged opossums show alterations in spatial learning behavior and reduced neurogenesis in the dentate gyrus.	in many mammalian species including opossums, adult neurogenesis, the function of which is not completely understood, declines with aging. aging also causes impairment of cognition. to understand whether new neurons contribute to learning and memory, we performed experiments on young and aged laboratory opossums, monodelphis domestica, and examined the association between spatial memory using the morris water maze test and the rate of adult neurogenesis in the dentate gyrus (dg). modification of ...	2019	31780889
influence of biological sex on social behavior, individual recogntion, and non-associative learning in the adult gray short-tailed opossum (monodelphis domestica).	social behavior is critical for relationship formation and is influenced by myriad environmental and individual factors. basic and preclinical research typically relies on rodent models to identify the mechanisms that underlie behavior; however, it is important to use non-rodent models as well. a major objective of the present study was to test the hypothesis that biological sex and social experience modulate the expression of social behavior in the adult gray short-tailed opossum (monodelphis d ...	2019	31465782
sequence alteration in the enhancer contributes to the heterochronic sox9 expression in marsupial cranial neural crest.	neonates of marsupial mammals are altricial at birth, because their gestation period is relatively short compared to placental mammals. yet, as they need to travel to the teat from the birth canal, and suckle on the mother's milk, forelimbs and jaws develop significantly early. previous studies in opossum (monodelphis domestica), an experimental marsupial model, have revealed that cranial neural crest cells are generated significantly early compared to those in placental mammals, such as mouse, ...	2019	31430446
progesterone signaling during pregnancy in the lab opossum, monodelphis domestica.	to investigate subtle pregnancy-associated changes in the lab opossum, monodelphis domestica, an induced ovulator, we compared pregnant with non-pregnant and pseudopregnant animals with regard to serum p4 levels and progesterone receptor (pr) expression. using video-verified, time-mated lab opossums as sources of biological material, we compared ovaries, uteri and sera obtained on odd-numbered days of the 14.5-day pregnancy in this animal. females that mated successfully but did not produce embr ...	2019	31254723
opossum milk igg is from maternal circulation and timing of transfer correlates with neonatal immune development.	marsupials, with short gestation times, have more complex and changing patterns of milk composition than eutherians. maternal immunoglobulins (ig) that confer immunity on offspring are among the components that change during marsupial lactation. in the present study we quantified the abundance of mammary transcripts encoding ig heavy chains and their corresponding transporters in the laboratory opossum monodelphis domestica. iga transcripts were the most abundant in opossum mammary and, with igm ...	2019	30414624
bone biomarkers in koalas: validation of assays and preliminary analyses.	traumatic injury, including bone fracture, is, to date, one of the leading causes of koala mortality in the south east queensland region of australia. further, the specialist diet of koalas, which is restricted to certain eucalyptus spp., may impact their normal bone physiology. considering the dramatic koala population decline and high incidence of trauma, a greater understanding of koala bone physiology may support conservation. we retrieved from genbank the protein sequences of parathyroid ho ...	2020	32917121
influence of temperature on motor behaviors in newborn opossums (monodelphis domestica): an in vitro study.	external thermosensation is crucial to regulate animal behavior and homeostasis, but the development of the mammalian thermosensory system is not well known. we investigated whether temperature could play a role in the control of movements in a mammalian model born very immature, the opossum (monodelphis domestica). like other marsupials, at birth the opossum performs alternate and rhythmic movements with its forelimbs (fls) to reach a teat where it attaches in order to continue its development. ...	2020	31097626
downregulation of trkc receptors increases dendritic arborization of purkinje cells in the developing cerebellum of the opossum, monodelphis domestica.	in therian mammals, the cerebellum is one of the late developing structures in the brain. specifically, the proliferation of cerebellar granule cells occurs after birth, and even in humans, the generation of these cells continues during the first year of life. the main difference between marsupials and eutherians is that the majority of the brain structures in marsupials develop after birth. herein, we report that in the newborn laboratory opossum (monodelphis domestica), the cerebellar primordi ...	2020	33013328
resistance of south american opossums to vwf-binding venom c-type lectins.	opossums in the clade didelphini are well known to be resistant to snake venom due to endogenous circulating inhibitors which target metalloproteinases and phospholipases. however, the mechanisms through which these opossums cope with a variety of other damaging venom proteins are unknown. a protein involved in blood clotting (von willebrand factor) has been found to have undergone rapid adaptive evolution in venom-resistant opossums. this protein is a known target for a subset of snake venom c- ...	2020	32135198
uterine epithelial remodelling during pregnancy in the marsupial monodelphis domestica (didelphidae): implications for mammalian placental evolution.	mammalian pregnancy involves remodelling of the uterine epithelium to enable placentation. in marsupials, such remodelling has probably played a key role in the transition from ancestral invasive placentation to non-invasive placentation. identifying uterine alterations that are unique to marsupials with non-invasive placentation can thus elucidate mechanisms of marsupial placental evolution. we identified apical alterations to uterine epithelial cells prior to implantation in monodelphis domest ...	2020	32052440
helicobacter monodelphidis sp. nov. and helicobacter didelphidarum sp. nov., isolated from grey short-tailed opossums (monodelphis domestica) with endemic cloacal prolapses.	in a search for potential causes of increased prolapse incidence in grey short-tailed opossum colonies, samples from the gastrointestinal tracts of 94 clinically normal opossums with rectal prolapses were screened for helicobacter species by culture and pcr. forty strains of two novel helicobacter species which differed from the established helicobacter taxa were isolated from opossums with and without prolapses. one of the helicobacter species was spiral-shaped and urease-negative whereas the o ...	2020	33079029